Adobe COLDFUSION 9 Manual page 321

DEVELOPING COLDFUSION 9 APPLICATIONS
Developing CFML Applications
You set the application name in the
application name is stored in the
Unlike client and session variables, application variables do not require that a client name (client ID) be associated with
them. They are available to any clients that use pages in the application.
Important: Place code that uses application variables inside
conditions from multiple accesses to the same variable. For information on using
cflock" on page 318.
Configuring and enabling application variables
To use application variables, do the following:
• Ensure that they are enabled in the ColdFusion Administrator. (They are enabled by default.)
• Specify the application name by setting the This.name variable in the initialization code of the Application.cfc or
by setting the attribute of the
name
Note: ColdFusion supports unnamed applications for compatibility with J2EE applications. For more information, see
"Unnamed ColdFusion Application and Session
The ColdFusion Administrator also lets you specify the following information:
• A default variable time-out. If all pages in an application are inactive for the time-out period, ColdFusion deletes
all the application variables. The Application.cfc file or
application. The default value for this time-out is two days.
• A maximum time-out. The application code cannot set a time-out greater than this value. The default value for this
time-out is two days.
You can set the time-out period for application variables within a specific application by using the
This.applicationTimeout variable of Application.cfc or the
Storing application data in application variables
Application variables are a convenient place to store information that all pages of your application might need, no
matter which client is running that application. Using application variables, an application could, for example,
initialize itself when the first user accesses any page of that application. This information can then remain available
indefinitely, thereby avoiding the overhead of repeated initialization.
Because the data stored in application variables is available to all pages of an application, and remains available until a
specific period of inactivity passes or the ColdFusion server shuts down, application variables are convenient for
application-global, persistent data.
However, because all clients running an application see the same set of application variables, these variables are not
appropriate for client-specific or session-specific information. To target variables for specific clients, use client or
session variables.
Using application variables
Generally, application variables hold information that you write infrequently. In most cases, the values of these
variables are set once, most often when an application first starts. Then the values of these variables are referenced
many times throughout the life of the application or the course of a session.
In circumstances that could result in race conditions from multiple accesses to the same variable, place code that writes
to Application scope variables or reads Application scope variables with data that can change inside
tag, normally on your application's Application.cfm page. The
cfapplication
Application.applicationName
cflock
tag for the current page.
cfapplication
scopes" on page 1131
cfapplication
applicationTimeout
Last updated 8/5/2010
variable.
tags in circumstances that could result in race
tags, see
cflock
tag can override this value for a specific
attribute of the
316
"Locking code with
tag.
cfapplication
tags.
cflock